Z1000 MK2 - Poor running in the 2-3000 rpm range

[njwmct]

If the slides are a bit high - then the raised needles will allow a bit more fuel thru

OK - but the slides were not high

[Pigford]

................... its a mystery

[njwmct]

Yes - the bike seems to have a mind of it's own

[Z1Boy]

I can hold a nice sweet idle by just holding the throttle open a tad, but if I adjust the idle stop screw to match the tiny throttle opening, when I rev it up it hangs....runs really sweet though. i'll do a balance tomorrow.

Late Z1A, 17.5 or 20 for the idle jet ?? Views??

Ta

[phil1r]

I've just had a problem like this, But not on a Z, it turned out to be float level to low. Can't believe no one has mentioned this.

[zpower]

I've just had a problem like this, But not on a Z, it turned out to be float level to low. Can't believe no one has mentioned this.

That was one of my initial thoughts too but he said he has done that in his initial post

Service Fuel levels - correct

So I guess thats why no one has mentioned it.

[njwmct]

I've just had a problem like this, But not on a Z, it turned out to be float level to low. Can't believe no one has mentioned this.

That was one of my initial thoughts too but he said he has done that in his initial post

Service Fuel levels - correct

So I guess thats why no one has mentioned it.

Yes the service fuel levels have been set very carefully as per the figures in the Kawasaki workshop manual.

[Z1Boy]

After fitting new plugs and doing 40 miles, I checked plug colour, all spot on except number 3 which is obviously a lot weaker than t'others. Thinking it could be something stupid like a bit of shite in the idle jet. Will check for a leak with WD40 before removing the carbs again though.

I think im getting close to sorting this goddam muthafukka...

[njwmct]

Spent a few more hours on the Mark II today - trying to sort out the hanging idle issue.
Anyhow after messing around for days setting the slide heights numerous times, checking for air leaks & changing plugs etc to no positive result.
I dropped the needles a notch today (back to clip position 3) & hey presto the hanging idle disappeared immediately!!
Weird! - I have absolutely no idea why lifting the needle one notch should cause the idle to hang.
Anyway, now seem to be moving back in the right direction.
I've also stuck with the larger #17.5 pilot jets as they seem to give the best idle.
Went for a ride on the bike & it seemed OK but the acid test is going to be from a cold start to see if the original misfire at 2000 rpm / surging at 3000 rpm is still there or not (the reason that I lifted the needles in the first place).

Update:
Well did a start from cold this week & although the throttle is no longer hanging - the hesitation at lows revs (which improves as the bike gets hotter) & surging at approx. 2800 rpm has returned - like the bike isn't getting enough fuel - the bike is however idling very well.

Jeff (jphaynes669) came round to offer a bit of help (much appreciated) - we checked out the fuel heights - the fuel flow/delivery to the carbs & all is good.

So to recap:

Needle on std pos. groove 3 - hesitation at low revs / surging at a 2800 rpm constant throttle.

Needle set at position 4 - no hesitation at lows revs or surging but the revs hang sometimes sticking at 2-3000 rpm & is very slow to return to idle.

Next step - going to shim the needles to effectively get a needle position of being at 3.5

[Z1Boy]

Further to my plug showing a weak number 3, I found the float height slightly low. Took the carbs off to adjust. Removed the new carb "manifold" rubbers and found number 3 wasn't seating quite properly, refitted with blue hylomar on all four. Re-assembled, now all sorted. ticks over sweet, hot or cold and doesn't hang.

Cheers

Andy

[njwmct]

Update on the Mark 2

Shimmed the needles to give an effective clip position of 3.5 from the top & carefully balanced up the carbs.
Things are looking promising
Did a cold start this morning - No misfire at 2-3000 rpm & no surging & no hanging idle.
Probably need to fine tune the idle mixture a little with a colourtune.

Before a full celebration gonna try another couple of cold starts but it looks like I'm finally getting somewhere - Thank F..k !

(Just amazes me as to how sensitive these bikes are to the smallest of carburation adjustments.)

[Pigford]

Just amazes me as to how sensitive these bikes are to the smallest of carburation adjustments.

Great thread - very useful info - glad the end is nigh

[zed1015]

Sounds like all your problems were due to the air leak on the inlet rubber as this will cause the hanging idle and misfires.
lifting the needles made an improvement because it slightly masked the air leak on that cylinder by enrichening the mixture.
The same goes when you fitted the larger pilots.
I would now put all the carb settings back to std.

[njwmct]

Sounds like all your problems were due to the air leak on the inlet rubber as this will cause the hanging idle and misfires.
lifting the needles made an improvement because it slightly masked the air leak on that cylinder by enrichening the mixture.
The same goes when you fitted the larger pilots.
I would now put all the carb settings back to std.

There was no inlet rubber leak on my Mark II - I think you are confusing my bike with that of 'Z1Boy'

[zed1015]

Sounds like all your problems were due to the air leak on the inlet rubber as this will cause the hanging idle and misfires.
lifting the needles made an improvement because it slightly masked the air leak on that cylinder by enrichening the mixture.
The same goes when you fitted the larger pilots.
I would now put all the carb settings back to std.

There was no inlet rubber leak on my Mark II - I think you are confusing my bike with that of 'Z1Boy'

Oh yeah! Bugger